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Prevent Paging while in an Atomic Environment

IP.com Disclosure Number: IPCOM000040970D
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Cebell, KS: AUTHOR [+3]

Abstract

Page faults are prevented during an atomic operation by checking the required storage locations and page faulting on only those that are not in main memory before performing the atomic operation.

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Prevent Paging while in an Atomic Environment

Page faults are prevented during an atomic operation by checking the required storage locations and page faulting on only those that are not in main memory before performing the atomic operation.

An algorithm in the Figure (when performed prior to an atomic operation) ensures that all storage locations involved in an atomic operation are in main memory and that interrupts are disabled. This is done without the overhead involved to pin the needed storage and is useful when the number of storage locations involved is small or likely to be in main memory.

The algorithm disables interrupts and checks to see if the needed pages are in main memory. If a page is found which is not in main memory, interrupts are enabled and a page fault is forced on only the missing page. After invoking this algorithm, the atomic operation can be performed prior to re-enabling interrupts. The algorithm is implemented with n-procedures: one to handle one address, another to handle two addresses, etc.

Disclosed anonymously

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